function GVerify(options) {
  //创建一个图形验证码对象，接收options对象为参数
  this.options = {
    //默认options参数值
    id: "", //容器Id
    canvasId: "verifyCanvas", // canvas的ID
    width: "100", // 默认canvas宽度
    height: "30", // 默认canvas高度
    type: "blend", // 图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母
    code: "",
  };

  if (Object.prototype.toString.call(options) === "[object Object]") {
    //判断传入参数类型
    for (var i in options) {
      //根据传入的参数，修改默认参数值
      this.options[i] = options[i];
    }
  } else {
    this.options.id = options;
  }

  this.options.numArr = "0,1,2,3,4,5,6,7,8,9".split(",");
  this.options.letterArr = getAllLetter();

  this._init();
  this.refresh();
}

GVerify.prototype = {
  /**版本号**/
  version: "1.0.0",

  /**初始化方法**/
  _init: function () {
    var con = document.getElementById(this.options.id);
    var canvas = document.createElement("canvas");
    canvas.id = this.options.canvasId;
    canvas.width = this.options.width;
    canvas.height = this.options.height;
    canvas.style.cursor = "pointer";
    canvas.innerHTML = "您的浏览器版本不支持canvas";
    con.appendChild(canvas);
    var parent = this;
    canvas.onclick = function () {
      parent.refresh();
    };
  },

  /**生成验证码**/
  refresh: function () {
    this.options.code = "";
    var canvas = document.getElementById(this.options.canvasId);
    if (canvas.getContext) {
      var ctx = canvas.getContext("2d");
    }
    ctx.textBaseline = "middle";

    ctx.fillStyle = randomColor(180, 240);
    ctx.fillRect(0, 0, this.options.width, this.options.height);

    if (this.options.type == "blend") {
      //判断验证码类型
      var txtArr = this.options.numArr.concat(this.options.letterArr);
    } else if (this.options.type == "number") {
      var txtArr = this.options.numArr;
    } else {
      var txtArr = this.options.letterArr;
    }

    for (var i = 1; i <= 4; i++) {
      var txt = txtArr[randomNum(0, txtArr.length)];
      this.options.code += txt;
      ctx.font = "20px SimHei";
      ctx.fillStyle = randomColor(50, 160); //随机生成字体颜色
      ctx.shadowBlur = randomNum(-3, 3);
      ctx.shadowColor = "rgba(0, 0, 0, 0.3)";
      var x = (this.options.width / 5) * i;
      var y = this.options.height / 2;
      var deg = randomNum(-30, 30);
      /**设置旋转角度和坐标原点**/
      ctx.translate(x, y);
      ctx.rotate((deg * Math.PI) / 180);
      ctx.fillText(txt, 0, 0);
      /**恢复旋转角度和坐标原点**/
      ctx.rotate((-deg * Math.PI) / 180);
      ctx.translate(-x, -y);
    }
    /**绘制干扰线**/
    for (var i = 0; i < 4; i++) {
      ctx.strokeStyle = randomColor(40, 180);
      ctx.beginPath();
      ctx.moveTo(
        randomNum(0, this.options.width / 2),
        randomNum(0, this.options.height / 2)
      );
      ctx.lineTo(
        randomNum(0, this.options.width / 2),
        randomNum(0, this.options.height)
      );
      ctx.stroke();
    }
    /**绘制干扰点**/
    for (var i = 0; i < this.options.width / 4; i++) {
      ctx.fillStyle = randomColor(0, 255);
      ctx.beginPath();
      ctx.arc(
        randomNum(0, this.options.width),
        randomNum(0, this.options.height),
        1,
        0,
        2 * Math.PI
      );
      ctx.fill();
    }
  },

  /**验证验证码**/
  validate: function (code) {
    var verifyCode = code.toLowerCase();
    var v_code = this.options.code.toLowerCase();
    if (verifyCode == v_code) {
      return true;
    } else {
      return false;
    }
  },
};

/**生成字母数组**/
function getAllLetter() {
  var letterStr =
    "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
  return letterStr.split(",");
}
/**生成一个随机数**/
function randomNum(min, max) {
  return Math.floor(Math.random() * (max - min) + min);
}
/**生成一个随机色**/
function randomColor(min, max) {
  var r = randomNum(min, max);
  var g = randomNum(min, max);
  var b = randomNum(min, max);
  return "rgb(" + r + "," + g + "," + b + ")";
}
